Tonality, the harmonic and melodic structure of musical notes, is a core element of music. Chromagrams, which can be represented using data structures, can be used as audio signal processing inputs in the computational extraction of frequency information, such as tonality information. A chromagram can be generated (e.g., calculated) by performing, for example, a Constant Q Transform (CQT), a Fourier Transform, etc. of a time window (e.g., a time frame) of an audio signal and then mapping the energies of the transform into various ranges of frequencies (e.g., a high band, a middle band, a low band, etc.).
The figures are not to scale. Wherever possible, the same reference numbers will be used throughout the drawing(s) and accompanying written description to refer to the same or like parts. Connecting lines or connectors shown in the various figures presented are intended to represent example functional relationships and/or physical or logical couplings between the various elements.